In recent years, enormous amount of plastic goods have been used such as those made of polyethylene, polypropylene, polystyrene, a polyester resin, an acrylic resin, and a polyvinyl chloride resin. The treatment of waste from these plastic goods has been highlighted as a growing environmental problem and has become a big social problem. Above all, a polypropylene resin is a material that is produced in the largest amount among all plastic materials, being used. For example, polypropylene resin used in bumpers of automobiles attributed to its light weight and stiffness. As a result the amount of polypropylene resin produced has been increased year by year. Consequently, polypropylene resin is one of the materials to which demand for recycling is the highest among various plastic materials. However, the polypropylene resin is essentially unstable against heat or light and is situated as a material having bad weather resistance. Therefore, investigation for antioxidants and hindered amine light stabilizers (HALS) which can improve light stability and thermal stability has been carried out for a long time.
For example, in Patent Document 1, there is proposed a technology in which a high molecular weight HALS is used to improve thermal stability in order to suppress lowering of performance due to bleed out of HALS from a substrate, which has been a conventional problem. In addition, in Patent Document 2, there is a description such that a polymer obtained by carrying out solution polymerization with a high concentration of a reactive HALS having both an unsaturated double bond and a light stabilizing function in a molecule is used as a stabilizer. Both of these technologies were insufficient judging from the performance directed to stability requirements which were becoming more sophisticated, though they could prevent the bleed out from a substrate resin, because they have a hindered amine group having a high polarity and hence could not realize sufficient dispersion performance of the HALS in the polypropylene resin which is a non-polar polymer.    Patent Document 1: Japanese Patent Application Laid-Open No. Hei 10-338,777    Patent Document 2: Japanese Patent Application Laid-Open No. 2003-40,937